The present invention relates to the use of ascorbic acid in hair care compositions, particularly in permanent waving and hair coloring compositions. More specifically, the invention relates to an oxidation system containing ascorbic acid, at least one metal ion, and an oxidizing agent which, when used in the inventive composition, is capable of generating an oxidizing potential of from about 100 to about 500 millivolts at a pH ranging from about 2 to about 10. The invention is also drawn to permanent waving and hair dyeing kits.
In permanent hair waving, the hair is first treated with a reducing composition capable of breaking the disulfide bonds of the hair keratin (Sxe2x80x94S) and causing the formation of sulfhydryl groups (xe2x80x94SH). In other words, the amino acid cystine in the hair is converted to cysteine. The hair is then re-shaped in a new form under applied mechanical tension, either by winding on rods (waving) or by combing through (straightening). The hair, while still under mechanical tension, is then subject to a neutralization step, during which the hair is treated with an oxidizing composition. The oxidizing composition causes the disulfide bonds of the hair keratin to be restored, i.e., reforming the amino acid cystine, and the hair now is capable of retaining the new configuration permanently.
The hair may be damaged if, during the neutralization step, hair is subjected to oxidants that are too strong. Over-oxidation generates cysteic acid instead of restoring the amino acid cystine. The presence of cysteic acid is undesirable because it does not allow the reformation of the disulfide bonds, resulting in weak, damaged hair.
In the art of permanent waving, the two most commonly used materials for quenching or neutralizing a permanent wave process are hydrogen peroxide and bromate salts. Each has its drawbacks. In permanent hair waving, the first step usually takes place at an alkaline pH of 7.5-10.0. The application of hydrogen peroxide, which is conventionally quite acidic, at pH 2.5-5.0, causes stress to the hair. Further, hydrogen peroxide may also xe2x80x9cliftxe2x80x9d the natural color of the hair and cause undesirable red undertones to develop. Bromate salts are used in some Asian countries as they will not redden hair like hydrogen peroxide. However, bromates are dangerous compounds in that they are explosive and ignitable.
Ascorbic acid, also known as Vitamin C, is widely used in the pharmaceutical industry and the cosmetic industry because of its biological activity. Attempts have also been made to use ascorbic acid in permanent waving of hair, both to break and to restore the disulfide bonds.
For example, in U.S. Pat. No. 2,780,579 to Schwartz et al., the oxidized form of ascorbic acid, i.e., dehydroascorbic acid (DHA), is taught as a perm neutralizer. The Schwartz et al. patent states that the powerful oxidants normally used in permanent waving, such as hydrogen peroxide, bromates, chlorates and chlorites, tended to over-oxidize the reduced hair. As a result, the oxidation goes beyond the cystine stage, resulting in irreversible damage to the hair. The over-oxidation renders the hair porous and brittle, and also causes hair discoloration. If lower concentrations of these oxidants are used, an insufficient disulfide bond recovery has been observed.
According to Schwartz et al., DHA is an effective oxidant, capable of converting cysteine back to the amino acid cystine in reduced hair without over-oxidizing the hair. Schwartz et al. used a mixture of ascorbic acid with hydrogen peroxide or other oxidants in the presence of buffers, forming DHA in situ.
Further, despite the statements in Schwartz et al. regarding the effectiveness of DHA, the reaction used therein is not much different from using peroxide alone. The molar ratio of ascorbic acid to hydrogen peroxide suggested in the examples of Schwartz was very high. This ratio was determined from Schwartz as follows:
(2 oz.xc3x9729 g/ozxc3x976%*) /(34 g/mol)=0.1 mol hydrogen peroxide
*20 vol. hydrogen peroxide=6% by weight in water
(0.25 g) /(176 g/mol)=0.0014 mol ascorbic acid.
RATIO=0.1 mol hydrogen peroxide/ 0.0014 mol ascorbic acid=72:1.
U.S. Pat. No. 5,270,337 to Graf teaches that the use of ascorbic acid and a divalent metal ion such as Cu2+ can effectively remove oxygen from an aqueous solution by converting the oxygen to water. In Graf, ascorbic acid reduces Cu2+ to Cu+ to form DHA. Cu+ (cuprous) ions form a complex with oxygen, and an electron transfer occurs to give Cu2+ (cupric) ions and superoxide anion radicals. The radicals, in the presence of the copper, rapidly disproportionate into oxygen and hydrogen peroxide. The copper-ascorbate complex quickly reduces the hydrogen peroxide to water without the simultaneous production of oxygen or hydroxyl radicals.
Graf""s invention is mainly used as a food preservative. Further, the copper-catalyzed degradation of peroxide taught in Graf does not solve the difficulty in the art of finding an effective peroxide-free permanent wave neutralizer and/or oxidation dye developing system.
Thus, it is desirable to develop an oxidizing system that would effectively restore disulfide bonds and/or develop oxidation hair color without using peroxides or bromates. In particular, it is desirable that the oxidizing system be able to accomplish this at a pH ranging from 5 to 10, preferably from pH 7.5 to 10.0. As discussed above, the first step in the permanent hair waving process usually takes place at a pH ranging from 7.5 to 10.0. The application of an oxidation solution in a similar pH range could be expected to be less stressful on the hair, as compared to the conventionally used hydrogen peroxide at a pH ranging from 2.5 to 5.0. In addition, such a system would be more compatible with oxidation hair dyes that are being developed in this same pH range, i.e., at a pH ranging from 7.5 to 10.0. Finally, this oxidation system would also provide for better color retention in tinted hair after permanent wave treatment.
Thus it was surprising and unexpected that the present invention, a system containing ascorbic acid, at least one metal ion catalyst, and an oxidizing agent capable of generating an oxidizing potential of from 100 to 500 millivolts at a pH ranging from 2 to 10 is an effective composition useful for application in place of peroxide for hair care applications.
To achieve these and other advantages, and in accordance with the purpose of the invention as embodied and broadly described herein, the present invention, in one aspect, provides an oxidizing system based on ascorbic acid and capable of effective restoration of disulfide bonds in reduced hair during the permanent wave process. The invention also provides an oxidizing system capable of developing color in oxidation dye systems. Further, the present invention provides an oxidizing system that does not render oxidative damage to the hair during permanent wave and/or color processing.
The present invention is thus drawn to an oxidizing system for application to keratinous substances, particularly human hair, the system containing ascorbic acid, at least one metal ion, and an oxidizing agent capable of generating an oxidizing potential of from about 100 to about 500 millivolts wherein the system has a pH ranging from about 2 to about 10.
The present invention is also directed to a method for using this oxidizing system to neutralize or xe2x80x9cquenchxe2x80x9d a permanent wave composition that has been applied to the hair. The oxidizing system of the invention is used after applying to hair an aqueous composition that serves to reduce disulfide bonds of the hair by the action of an organic mercaptan such as thioglycolic or thiolactic acid or its salts or bisulfites or phosphines. The ascorbic acid composition of the present invention is applied subsequently to re-oxidize the keratin disulfide bonds and thus to permanently reconfigure the hair.
Another aspect of the present invention is a method for using the inventive oxidizing system for the oxidation dyeing of hair without bleaching. The hair is dyed by applying a dye composition to the hair and then developing oxidative color, without bleaching, at acidic, neutral or alkaline pH using the oxidizing system of the invention, wherein the oxidizing system is added to the dye composition at the time of use either: (i) separately from the dye composition at the same time that the dyeing composition is applied to the hair or (ii) sequentially with the dye composition.
Yet another aspect of the present invention is a multi-compartment device or permanent wave or dyeing kit or any other multi-compartment packaging system, a first compartment of which contains either a permanent wave composition or a hair dye composition and a second compartment of which contains the oxidizing system as defined above.
Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed.
Reference will now be made in detail to the presently preferred embodiments of the present invention.
The oxidizing system of the present invention is useful for both the neutralization of a permanent wave and the development of an oxidation hair color because it does not redden or bleach the hair while quenching a permanent wave process or while developing hair color composition. Thus, the hair stylist has better control of the end results.
Using the inventive system, keratin sulfide is effectively transformed to keratin disulfide, without the increase in cysteic acid that occurs when either hydrogen peroxide or bromate are used. When the inventive oxidizing system is employed, no discoloration of hair due to the destruction of the melanin pigment in keratin occurs as it does when hydrogen peroxide comes in contact with hair. These observations indicate that a peroxide-free oxidant is formed in the inventive system.
Overall, when used in permanent hair waving, the novel oxidizing system demonstrates the following advantages, as compared to the conventional hydrogen peroxide (2% H2O2, pH 3):
Provides for a greater recovery of disulfide bonds
Prevents an excessive formation of cysteic acid
Sustains the tensile strength of the processed hair
Preserves the natural hair pigment
Provides for protection of oxidative hair color during permanent wave process.
When used in oxidation hair coloring, the present invention allows for development of a no-lift hair color, with less oxidative damage to the hair.
An additional aspect of the invention is that the oxidizing system can develop superoxygenated water solutions at will. Without being bound by theory, the inventors have found that when the presently claimed components of ascorbic acid and the metal ion are mixed into water and then the oxidizing agent is added, there is an apparent disappearance of all oxygen from the water followed by the increase of dissolved oxygen much in excess of that which is normally dissolved in water and without the bubbling of this excess oxygen from the water. This appearance of the superoxygenated water and lack of bubbling suggests that the action of the inventive system is not the chemistry of a metal-catalyzed degradation of peroxide but that there is another agent present when the components of the inventive system come together.
While the most preferred use of the present invention is in hair dyeing and permanent waving compositions, superoxygenated solutions as described above can also serve as oxygen suppliers to skin for personal care or act as a type of antiseptic to anaerobic bacteria.
Thus, the present invention is directed to an oxidizing system comprising: ascorbic acid, at least one metal ion and an oxidizing agent capable of generating an oxidizing potential of from about 100 to about 500 millivolts at a pH ranging from about 2 to about 10. Preferably, the oxidizing agent is capable of generating an oxidizing potential of at least about 150 millivolts at a pH ranging from about 7 to about 9. The ascorbic acid and the oxidizing agent are preferably present in a molar ratio ranging from about 1:2 to about 1:10, more preferably in a molar ratio of about 1:4 mol/mol.
The amount of the at least one metal ion preferably ranges from about 3 ppm to about 30 ppm. Preferably, the at least one metal ion is present in an amount of from about 15 to about 20 ppm.
Metal ions useful in acting as catalysts in the oxidizing system of the invention include copper, iron, manganese, magnesium, and mixtures thereof. Preferably, these metal ions are Cu2+, Fe3+, Mn2+, or Mg2+. More preferably, the at least one metal ion is Cu2+.
The source of the metal ions can be, but is not limited to, a metallo-sugar complex, or a complex of metal ions and other agents capable of complexation with metal ions such as peptides, amino acids and proteins. Useful metallo-sugar complexes include copper (II) gluconate, ferric (Ill) gluconate, manganese (II) gluconate, or magnesium (II) gluconate, or other sugars such as lactose, maltose, or sucrose. Preferably, the source for the metal ions to be used in the invention is copper (II) gluconate.
Other water-soluble salts of these divalent metal ions are also useful, such as the sulfate, ammonium, sodium, and potassium salts of these ions.
The oxidizing agent used in the present invention must be capable of generating an oxidizing potential, also called an electromotive potential or Emv, of from about 100 to about 500 millivolts at a pH ranging from about 2 to about 10. The preferred Emv is at least about 150 millivolts. It is also preferable for the oxidizing agent to be capable of achieving a rapid release of oxygen. The oxidizing agents useful in the present invention include but are not limited to alkali metal salts, ammonium salts, phosphate salts of perborate, percarbonate, persulfate, and peroxide, and mixtures of any of these oxidizing agents. Preferably, the oxidizing agent is sodium perborate, sodium percarbonate, potassium perborate, urea peroxide, or a mixture thereof. More preferably, the oxidizing agent is sodium perborate. When sodium perborate is used, it has been found that while it is not soluble in the ascorbic acid or the metal ion solution alone, it is very soluble in the combination of ascorbic acid and metal ion, particularly copper.
In a preferred embodiment of the novel oxidizing system of the present invention, the oxidizing agent is sodium perborate and the metal ion is Cu2+. In this preferred system, the ratio of ascorbic acid:sodium perborate is 1:4, mol/mol, e.g., 2 g ascorbic acid (0.01 mol) and 4 g sodium perborate monohydrate (0.04 mol), and the copper ion is present in the form of copper gluconate in an amount of 0.014 g (20 ppm Cu2+).
The pH of the oxidizing system of the invention ranges from about 2 to about 10. Preferably, the pH ranges from about 5 to about 10. More preferably, the pH ranges from about 7.5 to about 10.
The present invention may be used in the form of a kit. Thus, the inventive composition may be packaged in a multi-compartment device or permanent wave or dyeing kit or any other multi-compartment packaging system. In this device, kit, or packaging system, a first compartment contains either a permanent wave composition or a hair dye composition and a second compartment contains the oxidizing system as defined above.
The present invention also includes methods for the use of the oxidizing system described above. The novel oxidizing system of the invention can be used to develop oxidative color on hair without bleaching. Also, the oxidizing system of the invention is used in a method for quenching a permanent wave lotion that has been applied to human hair. These methods are similar in that they include the steps of applying a dyeing or permanent waving composition to hair and then applying, at the time of use, either (i) separately from the dyeing or waving composition at the same time that the dyeing or waving composition is applied to the hair or (ii) sequentially with the dyeing or waving composition, an oxidizing system comprising ascorbic acid, at least one metal ion, and an oxidizing agent capable of generating an oxidizing potential of from about 100 to about 500 millivolts at a pH ranging from about 2 to about 10.
With respect to dyeing, any dye composition known to the skilled artisan may be employed, such as those described in U.S. Pat. Nos. 4,226,595, 4,277,244, and 5,138,941.
With respect to the permanent wave process, any permanent wave lotion known to the skilled artisan may be employed. For example, ammonium thioglycolate, ammonium thiolactate, glyceryl monothioglycolate, or a combination thereof that may also contain thiolactic or thioglycolic acid at a pH ranging from 5 to 11, are permanent wave lotions known in the art. Such lotions are described by L. J. Wolfram, xe2x80x9cThe Reactivity of Human Hair: A Review,xe2x80x9d in Hair Research: Status and Future Aspects, C. E. Orfanos, W. Montagna, and G. Stuftgen, ed., Springer-Verlag publ., Germany 1981.
The invention will be illustrated by, but is not intended to be limited to, the following examples.